I was going to try it, then discover you have to install it after signing your life away.

http://safety.live.com/site/en-US/center/cleanup.htm

Nope, havent tried it.

And I dont intend to try it either.

I use it once or twice a month to check for viruses. It's the typical licensing stuff of any company.

Yeah, EULA's and restrictive licensing sucks.
"You agree that we take no responsiblity. You also agree that you may only use it. You may not copy, distribute, modify or give it to your friend. Blah blah blah. If you do, we will sue your ass."

That one always get's me.
So supposedly if the software sets my computer on fire which subsequently sets my home on fire they aren't responsible. It's about as silly as going to a sporting event such as baseball and they state if someone in the crowd is hit by the ball that they're not responsible.

I tried it, wasn't impressed. Didn't have any viruses for it to find, though, so it wasn't much of a test.

To safely test it or any anti-virus product do the usual by creating the harmless EICAR anti-virus test file on your system and let the anti-virus scan it. It's a good test to perform when using a new unfamiliar anti-virus product so that you know what to expect when it actually finds something malicious.